1. Field of the Invention
The present invention relates to a data processing apparatus, print job control method, and print data processing apparatus capable of preventing printing with unintended paper when, e.g., a printer with a plurality of paper feed units prints.
2. Description of the Related Art
A conventional printing system generally comprises a color or monochrome printer, a host computer (i.e., data processing apparatus) which controls the printer and generates print data (print job), and a communication interface which connects them.
Of printers, an inkjet printer can selectively use various print sheets in accordance with the application purpose. For example, the inkjet printer can utilize normal paper used in a copying machine or the like, coated paper prepared by coating the paper surface with silica or the like in order to suppress ink smudge and improve color development, and glossy paper used to form a photographic image such as a silver halide photograph. The inkjet printer can also print on a variety of print sheets such as an OHP film for a transparent document, and transfer paper and a back print film for iron print.
The inkjet printer can also process various print sheet sizes. For example, the inkjet printer can print on sheets of various sizes such as B5, A4, Letter, postcard size, card size, and L and 2 L photo sizes.
For this purpose, some printers have a plurality of paper feed units to supply sheets of various sizes from them. When the user selects a desired paper feed unit in printing, a printer of this type supplies paper from the selected paper feed unit to print.
For example, such a printer comprises a selection switch for selecting a paper feed unit. A choice representing a virtual paper feed unit, which is a paper feed unit indicated by the selection switch of the printer, is prepared as a choice for designating a paper feed unit on a print setting user interface provided by a host printer driver. When a print operation is done at print settings which designate a paper feed unit indicated by the switch of the printer, the printer operates to feed paper from the paper feed unit indicated by the selection switch (see, e.g., Japanese Patent Laid-Open No. 11-320854).
However, the conventional configuration suffers the following problems.
(1) A paper feed unit must be designated accurately in printing. In an environment where a plurality of users share a printer, for example, a user sets paper of a desired type and size in a proper paper feed unit. Alternatively, a paper type and size are determined for each paper feed unit. In this case, the user selects a paper feed unit loaded with desired paper with the paper feed selection switch of the printer, and executes a print job. In this operation, each user may change the selection switch to a paper feed unit for use. Before printing, the user must accurately recognize a paper feed unit selected by the paper feed selection switch, and the type and size of paper set in the paper feed unit.
(2) As a solution to problem (1), a sensor which detects the type and size of print paper may be arranged for each paper feed unit of the printer. In executing printing, whether paper can be fed is determined by comparing a type and size detected by the sensor with those of paper designated by print settings contained in a print job. According to this method, however, sensors must be arranged for all the paper feed units of the printer, increasing the printer manufacturing cost.